1. Field of the Invention
This invention relates to tunable lasers. Specifically it pertains to rapidly tunable lasers.
The increased use of lasers has led to interest in tunable lasers. The use of diffraction gratings and mechanical or electro-mechanical means are set forth in numerous prior art patents. However, all of these have been restricted due to limited deflection angle and thus narrow laser tuning range. Further limitations included relatively poor efficiency and moderate tuning rates.
As a relatively recent development stripe-domain light deflectors (SDLD) have been the subject of much experimentation. Stripe domains are ferromagnetic films with high Faraday rotation and low optical absorption which rotate the angle of polarization of light transmitted through (even-numbered domains) an angle .phi.=FT and through (odd-numbered domains) an amount -.phi., where F is the Faraday constant and T is the film thickness. The result of the differential rotation is that the film will act like a transmission diffraction grating. Since the orientation and spacing of the stripes may be altered by appropriate applied fields, the film may be used as a laser light deflector.
2. Description of the Prior Art
Studies by Johnsen, Hewitt, Kochel, and Torok on wide angle laser beam steering have provided insight into the effects of various materials for the stripe-domain material as well as methods and efficiencies of beam steering. All of this work was based on use of SDLD on the laser output.